Did you know that plants come in families?

You may remember learning taxonomy in your high school biology class. Way back when, I taught my classes of 15-year-olds the seven levels of classification: kingdom, phylum, class, order, family, genus, and species. (Since that time, scientists have been busy, and we now have domains, which precede kingdoms.) All these can have super- and sub- added to their names, as well. If you’re talking about plants, “phylum” is replaced by “division” and “order” is sometimes replaced by “series,” just to keep things as confusing as possible.

In addition, the various levels have standardized Latin endings, supposedly clarifying matters, and making the whole system a bit more international in flavor.

All living things have their place in this system. Let’s look at an example. Sticking to the primary taxonomic levels, that sprig of parsley on your plate is classified as:

Kingdom: Plantae
Division: Embryophyta
Class: Magnoliopsida
Series/Order: Apiales
Family: Apiaceae
Genus: Petroselinum
Species: crispum

After all that, you can have various varieties, or cultivars, such as Krausa, Italian Plain Leaf, and Lisette.

As we learn more about the relationships between various species, largely due to new studies of their genomes, taxonomists are having a rousing good time organizing and reorganizing the family tree. Currently, the entire field of plant taxonomy is in disarray, as seen by this list of parsley synonyms:  Apium petroselinum, Carum petroselinum, Petroselinum hortense, Petroselinum sativum, and Petroselinum vulgare. Unfortunately, this is fairly typical. (If you’re looking to do research in a field with terrific job security, may I suggest plant taxonomy.)

All this is doubtless very useful for botanists, but thankfully, as gardeners, we can pretty much ignore everything above class. Having a basic knowledge of the most common plant classes, however, will not only help you identify plants, it can also help you know how best to tend them.

Current estimates put the number of known vascular plant species (all plants except algae, mosses, liverworts and hornworts) at around 391,000, with approximately 2,000 more added every year. The vast majority of these (94%) are flowering plants such as daisies, grasses, and tomatoes. Even the most devoted gardener will find this number overwhelming. That’s why it helps to combine species into families.

According to one authority, there are 642 families of plants. Other estimates vary widely. The largest families are the sunflower family (Asteraceae or Compositae):

The orchid family (Orchidaceae):

And the pea family (Fabaceae, aka Caesalpiniaceae, Fabaceae, Mimosaceae, Papilionaceae, and formerly called Leguminosae. What a mess!

Here are some other plant families that you may recognize:

Amaranthaceae – Pigweed:

Apiaceae (formerly Umbelliferae) – Carrots:

Boraginaceae – Borage:

Brassicaceae (formerly Cruciferae) – Cabbages:

Campanulaceae – Bellflowers:

Caryophyllaceae – Pinks:

Convolvulaceae – Morning Glories:

Euphorbiaceae – Spurges:

Lamiaceae (formerly Labiatae) – Mints:

Malvaceae – Mallows:

Papaveraceae – Poppies:

Poaceae – Grasses:

Ranunculaceae – Buttercups:

Rosaceae – Roses:

Scrophulariaceae – Figworts:

Solanaceae – Nightshades:

The families are often easily discerned by looking at the stems, leaves, flowers, and seeds of a plant. You may recognize similarities in these photos. And if you’re trying to identify a particular flower or weed, you’ve just narrowed things down to a select group of possibilities.

Over the next year or so, I’ll be writing about many of these plant families, mainly those I think are most helpful for gardeners to know. Join me as we get a bit botanical!